Psoriasis is a chronic skin disorder that is proliferative in nature and widespread throughout the world, afflicting millions of humans and even domesticated animals having similar proliferative integument problems. The skin disorder is characterized by recurrent, elevated red lesions, plaques or rarely pustules on the skin. These plaques are the results of an excessively rapid growth and shedding of epidermal (skin) cells.
No one knows what causes this abnormal cell proliferation. Its severity and course vary greatly from case to case, and also in the individual afflicted with the disease. Recurrences are almost the rule with intervals varying from one month to many years. One person may go through life with a single patch on the elbow, knee or scalp, while another will have repeated attacks of a generalized eruption or widespread chronic lesions lasting for years without remission. As discouraging as it may be, medical science and literature are replete with indications that patients exhibiting such lesions are destined for life to be "psoriatic." With all of the advances in medical science, no one knows what causes this abnormal cell proliferation. With some of it, it is felt that some type of biochemical stimulus triggers this abnormal cell growth. It is still unknown whether the origin of this biochemical malfunction resides in the skin, in the immune system, in the white blood cells, or is possibly psycho-neural. It is known that certain environmental factors can "trigger" the initial appearance or worsening of psoriasis. Conversely, the symptoms can spontaneously clear for reasons scientists do not understand. Treatment of the psoriasis is aimed at clearing the lesions for as long as possible. This is what is meant by the term "remission" or "clearance." In any event, medical science has fairly well agreed that psoriasis is an heritable disease in which the specific defect seems to be unknown.
For years there have been many attempts to treat the disease, and several topical and systemic treatments for psoriasis which inhibit cell division have been with limited success in clearing the skin for short periods of time. Yet, the reason why these treatments work is not yet clearly understood. Treatments which have been suggested in the art appear to be symptomatic and palliative. Lesions may disappear spontaneously or as a result of the therapy, but recurrences are likely. There is a tendency for each remedy gradually to lose its effectiveness or develop dangerous accumulative toxicity. Rarely, however, is the disease apparently cured, showing no evidence for years.
In the treatment of the disease, medical science has suggested low fat or low protein diets. Drugs such as systemic corticosteroids and ACTH are effective but limited to patients who are in great distress and do not respond to other measures. Such drugs may produce dangerous side effects; and in some instances, once the drugs are discontinued, the eruption may show a marked exacerbation. Folic acid antagonists have been found to have some beneficial treatment but are a dangerous form of therapy. Although other drugs have been suggested, for the most part the serious side effects associated therewith have not made them successful. Ionizing radiation therapy, e.g. grenz-ray treatment, has provided only temporary benefit, but the danger(s) of addiction to such radiation producing radiodermatitis and subsequent carcinoma is not worth continued treatment. Corticosteroid ointment in combination with polyethylene film has had some success, but systemic effects may be caused by extensive use. Ointments have been found to be more beneficial than lotions. A typical ointment may contain anthralin or tar. Hydrophilic ointment containing salicylic acid and sulfur is also found to be beneficial, especially for scalp treatment. Here again, the side effects and the absorption within the human system of these chemicals must be guarded. Other treatments including sunlight baths or ultraviolet (UV) baths with the lesions painted with a solution of coal tar, anthralin or psoralens have been found to be helpful.
Ongoing studies in the art concern the use of vitamin D.sub.3 (1,25-dihydroxivitamin D.sub.3). Etretin and Etretinate are new generation retinoids presently being studies for treating psoriasis, but again, the side effects must be carefully monitored.
Other ongoing studies include the use of the drug cyclosporine, RS 53179 (a non-steroidal, anti-inflammatory drug), fish oil, hypothermia, and anti-yeast agents.
One method for alleviating psoriasis is taught in U.S. Pat. No. 4,181,725 which teaches a pharmaceutical compound which contains as its active components at least one compound selected from the group consisting of parabromophenacyl bromide, alpha tocopherol, mepacrine, chloroquine, hydroxychloroquine, dibucaine, tetracaine, lidocaine, butacaine, procaine, ethylene diamine tetra, acetic acid, and ethylene glycol bis (.beta. amino ethyl ether) -N-N'tetracetic acid within a suitable carrier.
Seborrheic dermatitis (seborrhea) in the least severe form, but most common, is simple dandruff. It can become more severe and form scaly, red patches on the face, ears, chest, and other widespread areas. It often coexists with psoriasis, and many subjects have overlapping features termed "seborrhiasis." Therefore, a continuum may exist whereby these are on the same disease spectrum. Treatments are similar to those currently used for psoriasis, although lower dosages are usually sufficient to control seborrheic dermatitis.
Eczema (including but not limited to atopic, nummular and hand types) often has similar overlapping features with psoriasis. See, e.g., H. Roenigk, Jr. et al., "Psoriasis" , .COPYRGT.1991, Marcel Dekker, Inc., Chapter 2. For instance, it is often difficult to distinguish based on clinical appearance. They can coexist, or the disease can begin as eczema and over time turn to psoriasis. Again, treatments are similar with corticosteroids and tar preparations commonly employed for both of these conditions.
Similar conditions to both seborrheic dermatitis and eczema also occur in various domestic animals (mange, etc.). The current invention is felt to encompass all similarly involved species.
Seborrheic dermatitis and eczema have several other features in common with psoriasis. They are very common in the general population. They have no known cause, although many theories are advanced. They have no known cure, although many similar temporary remedies are known. All of these conditions are known to worsen with stress. Finally, there seems to be a hereditary basis or tendency for development of each of these skin disease, although this is not a strict finding.